1. Field of the Invention
The present invention relates to mechanical devices for the control of a gas flow, and, more particularly, to a mechanical valve assembly utilized therein.
2. Description of the Related Art
In many applications, a flow of gas is required to operate various appliances. Some appliances, for example, include fireplaces, stoves, ovens, furnaces, heaters, etc. Because of inherent sudden and/or unforeseen circumstances surrounding the use of such apparatuses, it is desired to be provided with a way of controlling the gas flow in general, and shutting off the gas flow in particular.
It is known in the art to have separate valves for controlling gas flow: a primary valve that is used to turn on and off the gas flow in normal operations, and a separate electrically-operated valve to shut off the gas flow. The latter valve is sometimes referred to as an “emergency shut-off” valve. The function of the emergency shut-off valve is to completely stop the flow of gas to the appliance until various courses of action are taken.
Depending upon the types of valves and the applications in which they are used, various problems can be encountered. One problem is the reliance of the emergency shut-off valve upon electricity. In an urgent situation where the power source may be unreliable or completely absent, the emergency valve would fail to operate and thereby allow the gas flow to continue unabated. Further, an electrical connection may not be reliable and prone to disruption.
Another problem that can be encountered is the distance between the two valves. If the emergency shut-off valve is at a distance from the primary valve, there may be a lag in the time an urgent situation is noted and the emergency shut-off valve is actuated. Furthermore, the distance can create more opportunities for failure as a result of additional conduits, wiring, etc. between the two valves.
What is needed in the art is an apparatus to reliably shut off a timed flow of gas in an urgent situation.